In recent years, purchasers of swimming pools, particularly private pool owners, have demanded an increased number of convenience accessories for their swimming pools. Amoung such accessories are covers or domes, decorative strips or fiber optic or other lighting means, sports equipment such as water volley ball net tie down means, and the like. The use of brackets, eye-bolts, and the like, conventional fasteners, as the holding means for an accessory, are unsightly and hazardous because such holding means protrude and can cause injury to the swimmer. A convenient, safe and obscure place to locate such securing means is on the coping element, i.e., below the top cap of the coping and as an integral part of the coping element. In the past, generally it has been sufficient to provide a single channel, or at most two channels as the holding mechanism. Such channels have been formed as a part of the coping element. In the case of a single channel, the channel is devised for use in securing a flexible plastic liner; the liner being suspended from a bead formed at the top of the liner and inserted and held in the channel formed below the top cap of the coping. In structures where a dual channel has been provided, the second channel is usually held available to accomodate a pool cover. Illustrative examples of two-channel prior art coping structures are those disclosed in U.S. Pat. Nos. 3,628,198, 4,429,425 and 4,457,119. In practice, however, with the advent of various other convenience accessories, such second channel is frequently occupied, or is desired for occupation, by another accessory such as a decorative trim or a fiber optics light strip. In the latter case, if the channel is to be available for use by the cover securing bead, such decorative insert or other accessory which is already in place must first be removed. Because of the considerable inconvenience involved in removing an and storing an installed accessory when it is desired to install an additional accessory, such as a pool cover, if the top securing channel is occupied, the provision of additional securing means affords a substantial advantage. Accordingly, a need exists for an arrangement that will conveniently and safely accomodate securing means for additional accessories in the coping structure.